Metro Detroit weather: Monitoring a severe storm risk

Showers, thunderstorms increase as warm front pushes north


DETROIT – Showers and thunderstorms south of us are increasing as a warm front pushes north, and the overnight hours will feature some of those showers and possibly a thunderstorm crossing the area. No severe weather is expected tonight, so rest easy (even if nighttime thunder and lightning make you nervous).

The warm front will usher in a much warmer and more humid air mass, thus continuing the temperature roller coaster we’ve been on. Lows in the low to mid 60s (16 to 18 degrees Celsius) will probably occur in the middle of the night, with temperatures slowly rising after that toward dawn. East winds at 7 to 12 mph ahead of the warm front will shift to the south after the front passes by.

We have a shower chance at any point during the day Tuesday, but parts of the day will be dry as well. Based upon satellite images we’ve been monitoring this afternoon, the warm sector behind the warm front is what we call a “dirty” one -- in-other-words, there’s a lot of cloud cover, which should hold highs in the mid to upper 70s (25 to 26 degrees Celsius).

However, should any breaks of sun develop during the afternoon, then we’d easily hit 80 degrees (27 degrees Celsius), and also have to introduce a pop-up thunderstorm in the afternoon.

Tuesday’s sunrise is at 7:24 a.m., and Tuesday’s sunset is at 7:25 p.m.

Tuesday night has been at the top of our list of things to monitor since last week, as a strong cold front crashing into the warm, muggy air mass overhead will trigger some thunderstorms.

Of greater concern is that the winds will increase steadily as you head aloft -- to 60 to 70 mph by 18,000 feet or so. This change in wind speed is called speed shear, and increases the chance for organized severe thunderstorms. However, the cold front won’t approach until after midnight -- the most unfavorable time of day from an instability standpoint.

At this point, just given the basic dynamics of this situation, we need to express concern about potential damaging wind gusts Tuesday night, but this is a fluid situation that we’ll update you on tomorrow here on ClickOnDetroit.com, on our free Local4Casters app and, of course, on Local 4.

After a possible lingering shower to start the day on Wednesday, skies will gradually become mostly sunny during the day. Highs will be cooler -- back into the upper 60s (20 degrees Celsius).  It’ll also become a windy day.

Mostly clear Wednesday night, with lows in the upper 40s (9 degrees Celsius).

Partly cloudy both Thursday and Friday, with highs in the mid to upper 60s, respectively (19 to 20 degrees Celsius), and overnight lows in the upper 40s to low 50s (9 to 11 degrees Celsius).

Weekend forecast

The models disagree greatly about a weak upper level disturbance crossing the area to start the weekend. One model (the GEM) actually keeps us dry, another model (the GFS) holds off the rain until Saturday night, and another model (the ECMWF) simply throws a few showers at us first thing Saturday, before clearing us out.

We’ll probably need a couple of days to sort this out but, at this point, plan on at least the chance for a shower on Saturday -- but not necessarily a rained out day -- with highs in the mid 60s (19 to 20 degrees Celsius).

Sunday looks like a fine autumn day, with partly cloudy skies, and highs in the mid to upper 60s (19 to 20 degrees Celsius).

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